Problem: Khan.scratchpad.disable(); To move up to the maestro level in her piano school, Gabriela needs to master at least $81$ songs. Gabriela has already mastered $39$ songs. If Gabriela can master $10$ songs per month, what is the minimum number of months it will take her to move to the maestro level?
To solve this, let's set up an expression to show how many songs Gabriela will have mastered after each month. Number of songs mastered $=$ $ $ Months at school $\times$ Songs mastered per month $+$ Songs already mastered Since Gabriela Needs to have at least $81$ songs mastered to move to maestro level, we can set up an inequality to find the number of months needed. Number of songs mastered $\geq 81$ Months at school $\times$ Songs mastered per month $ +$ Songs already mastered $\geq 81$ We are solving for the months spent at school, so let the number of months be represented by the variable $x$ We can now plug in: $x \cdot 10 + 39 \geq 81$ $ x \cdot 10 \geq 81 - 39 $ $ x \cdot 10 \geq 42 $ $x \geq \dfrac{42}{10} \approx 4.20$ Since we only care about whole months that Gabriela has spent working, we round $4.20$ up to $5$ Gabriela must work for at least 5 months.